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In this paper, we develop a new approach that combines the spectral clustering method and input–output analysis to detect environmentally important supply chain clusters. The newly developed method was applied to automobile manufacturing in Japan, and major clusters with high energy intensities in the automobile supply chain were identified. This paper proposes that the car manufacturers will be able to regularly publish their life-cycle assessment reports with a focus on the indirect energy consumptions within the critical supply chains and request key auto-part manufacturers in the cluster to reduce the indirect consumptions through the relevant supply chain engagement. [ABSTRACT FROM AUTHOR]

This paper is concerned with the main activities of Japan's 'Disclosure of CO2 emissions' programme, aimed at illustrating the CO2 emissions associated with consumer products as a 'carbon footprint' (CF). Although the current, provisional guidelines for calculating product carbon footprints specify that only the bottom-up approach is to be used for this purpose, this paper presents useful applications of input-output analysis that can improve the reliability of the method considerably, by taking full advantage of the strengths of input-output analysis. To this end, we first estimated the global carbon footprint (GCF) of food and consumables in Japan, using a global link input-output (GLIO) model comprising 804 economic sectors in Japan and 230 foreign countries and regions. By visualizing the GCF on a world map, the global distribution (including Middle East and African countries) of the induced CO2 emissions of each of the Japanese sectors were identified. To investigate the scope for reducing the data collection burden for CF practitioners, GCFs were compared with CFs obtained using a single-region input-output model. This showed that there are certain commodity groups with a CF equating to 70% to over 90% of the corresponding GCF, even if the imported goods used for producing a Japanese domestic product are considered environmentally equivalent to their domestically produced counterparts. Furthermore, it was identified which data should preferably be collected by the bottom-up approach to secure CO2 emissions coverage greater than a certain predefined level and keep data and labour costs at a minimum. [ABSTRACT FROM AUTHOR]

Today's material welfare has been achieved at the expense of consumption of finite resources and generation of environmental burdens. Over the past few decades the volume of global consumption has grown dramatically, while at the same time technological advances have enabled products with greater efficiencies. These two directions of change, consumption growth and technological advance, are the foci of the present paper. Using quantitative measures for these two factors, we define a new indicator, ‘eco-velocity of consumption’, analogous to velocity in physics. The indicator not only identifies the environmental soundness of consumption growth and technological advance but also indicates whether and to what extent our society is shifting toward sustainable consumption. This study demonstrates the practicability of the indicator through a case study in which we calculate the eco-velocities of Japanese household consumption in 2 years: 1995 and 2000. The rate of technological advance during the periods concerned is quantified in terms of the embodied carbon dioxide emission per yen of product. The results show that the current growth rate of Japanese household consumption is greater than the rate of technological advance to mitigate carbon dioxide emissions. The eco-velocities at the level of individual commodity groups are also examined, and the sources of changes in eco-velocity for each commodity are identified using structural decomposition analysis. [ABSTRACT FROM AUTHOR]

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input-output LCA method with a global link input-output model that defines a global system boundary grounded in a simplified multiregional input-output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input-output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains.

In recent years, greenhouse gas emission controls that incorporate the supply chains of products and services, thereby emphasizing the role of consumers rather than producers, have been drawing increasing attention. A country's consumption-based emissions, including those due to global supply chains, reflect the total emissions on which the national economy relies. To design effective emissions control strategies there is therefore an urgent need for countries to elucidate the structural relationship between their domestic economy and emissions occurring through global supply chains. Here we consider the structural characteristics of consumption-based emissions in Japan, which in 2005 totaled 1675 Mt CO(2)eq. Outside the country the Japanese economy generated global emissions of 541 Mt CO(2)eq, 35.7% of which were UNFCCC Annex I emissions and 64.3% were non-Annex I and other emissions. This figure of 64.3% reveals that Japan is actually relying to a considerable degree on emissions that are subject to no international obligations. We identify key economic contributors to consumption-based emissions at the commodity level and specify items of household expenditure that are effective options for both financial savings and emissions reduction. We then discuss the importance of emissions control for evolving toward a "carbon-debt-free country".

As the services industry has grown and diversified, there has been a rapid rise in the share of energy and material costs in provision of services. As a result, services, which have traditionally been considered immaterial by their nature, are now absorbing substantial amounts of energy and material goods. By decomposing the CO2 emissions embodied in material goods and services, this study quantitatively analyzes the implications of energy and materials consumption in services for the change in indirect CO2 emissions by household consumers in Japan. The results show that the domestic CO2 emissions associated with the energy and material goods absorbed by services through the supply chain increased consistently during the decade 1990-2000, thereby constituting a key element in the rise in CO2 emissions due to household consumption. The energy and materials within the supply chain underlying services that have been identified as the main causes of this increase include electric power consumption, petroleum products, building renovation and repair, distribution of printed materials, plastic products and water, all of which are necessary to support the services in question. This study highlights the increasing importance of energy and materials consumption by services in the context of climate change policy.

The evolution of crude oil use structure and its impacts on commodity prices are examined for Japanese economy between 1990 and 2000. We found that the out-degree of the production network, indicating the extent of the pressure on prices of downstream industries in response to higher crude oil prices, decreased in several sectors between 1990 and 2000. The results by sector showed that the decrease was greatest in the chemical product- and iron and steel manufacturing sectors, which both indirectly use crude oil. The decrease in out-degree is considered to have been caused by improved efficiency in the production of oil-related products and increase in energy savings by the manufacturing facilities in these sectors. In addition, many of the sectors having a high out-degree engage in intermediate product production. Conversely, the in-degree, which represents the extent of being pressured by other sectors with increased crude oil prices, also decreased during the period between 1990 and 2000. From the result of the in-degree, this study found that dematerialization and weight reduction of final products such as "cellular phones" and "personal computers" had a marked effect on decreasing in-degree. More importantly, for the top-ranked sectors with the high out-degree and in-degree, such as "aliphatic intermediates", "chemical fertilizers", "plastic products", "hot rolled steel", "yarn and fabric dyeing and finishing", the results suggest that the pressure due to rising crude oil prices can be more effectively eased by implementing measures targeted at upstream products and sectors, while current policy measures to alleviate oil-price induced inflation are mainly targeted at downstream products such as gasoline.